According to what I heard is that 2NE1 members renewed their contracts with YG Entertainment but Minzy didn't and the fully respected her decision. Also they felt sorry more than unsatisfied about her decision.

YG Entertainment has announced that they will make an official announcement regarding 2NE1's rumors on April 5.

Another reporters said
"It's a sad day in the K-pop world as one of its most beloved groups loses a member.
Following reports that 2NE1 member Gong Minzy was in talks with other labels, YG Entertainment (home to PSY, BIGBANG, Epik High, Lee Hi, among other international favorites) put out a statement and revealed that the 22-year-old singer/dancer would not be continuing on with the group after declining to renew her contract with the agency. The label said its other three 2NE1 members—CL, Dara, and Bom—expressed interest in continuing the group, but Minzy felt otherwise.
The youngest member of 2NE1, Minzy spent five years training and preparing for her K-pop career before her 2009 debut in the foursome. 2NE1 has been on a break since releasing their chart-topping album Crush in 2014.
The label assured fans that 2NE1 would continue with the three remaining members, and that the threesome is currently preparing new music that's anticipated to be released this summer. There are no plans to add a new member."

@CreeTheOtaku yeah i wish her the best.
I do tend to forget she is the youngest memeber too, so I was like no she wont do anything else!
But maybe we'll get a female Jay Park? He did better on his own too. eho knows we'll see